It is known to couple optical fibers in cassettes. Such cassettes for coupling optical fibers are known for example from U.S. Pat. No. 6,282,360 B1, it being possible for the optical fibers to be received by the cassettes with an excess length for a splicing reserve. The cassettes are designed in such a way that the excess lengths of the optical fibers can be received while at the same time a minimum bending radius is maintained. For access to the optical fibers in a cassette, it is known to form the cassette in such a way that it is movable in relation to a receiving element.
A device for coupling optical fibers in cassettes is also known from DE 102 55 561 A1. In a receiving element formed as a module, a number of cassettes are arranged in such a way that they can in each case be pivoted in relation to the receiving element and, in addition, are releasably connected to the receiving element. This makes it possible for the excess length or excess lengths of the optical fiber(s) received in the cassette to be unwound and for the connection of the optical fibers to be performed at a workplace specially prepared for this, which is spatially separate from the receiving element.
In the case of the known devices, the receiving element is in each case formed in a modular manner in such a way that it can receive a number of cassettes. However, the maximum number of cassettes that can be received is not variable. This means that this maximum number of cassettes that can be received is fixed when the receiving element is produced.
In the case of the known modular receiving elements, it is in each case provided that optical fibers, which are preferably led in to the receiving element by means of one or more buffered fibers, are led in largely from one direction. In the mentioned DE 102 55 561 A1, provided for this purpose is an opening which opens into a funnel-shaped channel, in which optical fibers led in by means of buffered fibers are individually separated and passed to the individual cassettes. A clearly arranged organization of individual optical fibers in the funnel-shaped channel is possible only with difficulty. In particular during servicing work, in which, following initial installation, individual optical fibers are to be exchanged or connected to different optical fibers than before, this is very disadvantageous. There is a high risk of individual optical fibers that are not specifically being worked on being damaged during such servicing work. Damage to these optical fibers is generally not noticed by the engineer carrying out the servicing, since not all the optical fibers connected to one another in all the cassettes can be checked after a servicing procedure on account of the great effort this involves.
Although a number of inlets are provided in the case of the device known from U.S. Pat. No. 6,282,360 B1, they likewise open out into a common leading-in channel, which however has a number of rudimentary guiding elements and additional guiding elements leading to the individual cassettes. Furthermore, there is a description of an embodiment in which the leading-in channel just described is formed doubly, the two leading-in channels formed being made to extend parallel to each other. A disadvantage of this embodiment is that the inner leading-in channel is covered by the outer leading-in channel, so that access to the inner leading-in channel during servicing work is in many cases impossible. In the other cases, access is at least not possible without all the optical fibers that are guided in the receiving element being greatly affected. There is consequently a high risk of optical fibers being damaged.
In the case of both known devices, it is provided that the one or more buffered fibers or the individual optical fibers are all led in to the receiving device largely from one direction. As a result, a clearly arranged and easy-to-service construction of a distributing unit in which these receiving elements are usually used together with the cassettes for coupling optical fibers is possible only with difficulty or not at all.